Grate Temp differential


 
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ChadVKealey

TVWBB Pro
I'll be cooking two butts (on ~8 lb., the other ~9) tomorrow night for a party Saturday at 4. I'm planning to get them on around 10 PM and trusting my new PartyQ to keep the temp at or near 250 overnight. I have fresh batteries on hand in case they don't make it. My only question is placement of the butts and the PartyQ probe.

I believe (though I've not measured myself) that the lower grate is usually a bit cooler than the top grate. If it matters, I use foiled bricks in the water pan with a triple layer of foil on top to catch drippings. So, I was figuring I'd put the smaller butt on the bottom (due to the slightly cooler temp) and put the bigger one on the top grate. I actually have two Mav ET-732s, so I can probe them each separately.

As for the PartyQ sensor, I was going to stick that right in the hole in the silicon grommet rather than clipping it to one of the grates or a meat probe. I think (though I could be wrong) that that placement will give me a better picture of the average temp in the smoker. Thoughts on this?
 
Chad,

Although mine is a pre silicon grommet WSM, that is basically where my ATC's probe is located. Some will tell you it is the hot spot. It is! It's also the temperature of the air being supplied to the cooking area, if running w/o water in the pan. Since each butt most likely came from a different animal, and no two animals are the same, there is no way to guarantee the smaller butt will cook faster.

If you were to check at same relative height but at different locations around the circumference, air temperature is not the same. Usually varies by a couple of degrees.

Keep an eye on how the butts are progressing. If you see that you may run short of time use some tools such as increasing pit temperature and/or foiling to make needed corrections.

Wishing you a delightful, enjoyable, and tasty cook.
 
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Chad, how long is the probe for the PartyQ sensor. Since the heat on a WSM goes up around the water pan and up the sides of the WSM (giving us indirect heat), the outer edges are hotter than the middle of the grates. If that sensor doesn't push in 4-6", it will be reflecting that higher heat. As you can see from the following picture, I just push my Maverick pit temp probe through the grommet, but that probe is 6" long.

Maverick02_zps52d145e1.jpg


What size is your WSM? I have the 22.5 and *could* put 3 butts on each rack. I have done 4 (2 on each rack) before. One of the two on the bottom took longer to cook.
 
I have an 18.5. The PartyQ probe is pretty short (probably about 4"?), and I tried just poking it in, but it was reading 40 degrees hotter than my maverick's pit probe on the lower grate. So, I just pulled it through and clipped it to the mav's pit probe.

I put the two butts in last night at about 9:30. I loaded it up with a mix of RO lump and KBB, 2 chunks each of hickory and pecan mixed in, and put a half chimney of lit KBB on top. It ran great through the night, but by 8:00 this morning the temps were dropping and a visual check showed that the fuel was running low, so I added another chimney of lit KBB and changed the batteries in the PartyQ (mental note: need to do the AC adapter mod before the next long cook). Next overnight, I'll go with straight KBB and skip the lump, or maybe just use lump to get it started.

As far as the temperature differential between the grates, the top one has been anywhere from 5 to 40 degrees higher than the bottom. I've been checking/recording the temps every half hour, at least every half hour I've been awake here. Taking a quick peek when I added the charcoal, they look fantastic. They seem to be working through the stall little by little and if they're not in the 190 range by noon, I'll foil 'em up to finish (though I'm hoping to avoid that). When they're done, I'll be sure to post pictures.
 
I took both butts off the smoker at 2:15. At that point, the top one was at 192 and the bottom at 189. After an hour of resting and shredding, this is what I got:


Some more pics available here. I packed all of it into our big crockpot and took it to a party where it was thoroughly enjoyed by 30-40 guests.
 
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